fix darwin flake

flake.nix

@@ -60,9 +60,6 @@
       # The platform the configuration will be used on.
       nixpkgs.hostPlatform = "aarch64-darwin";
 
-      # Necessary for using flakes on this system.
-      nix.settings.experimental-features = "nix-command flakes";
-
       # Set Git commit hash for darwin-version.
       system.configurationRevision = self.rev or self.dirtyRev or null;
 
@@ -80,6 +77,22 @@
           ShowStatusBar = true; # show status bar
         };
       };
+
+      # Auto upgrade nix package and the daemon service.
+      services.nix-daemon.enable = true;
+
+      nix = {
+        configureBuildUsers = true;
+        distributedBuilds = true;
+
+        gc = {
+          automatic = true;
+          options = "--delete-older-than 7d";
+        };
+        settings = {
+          experimental-features = "nix-command flakes";
+        };
+      };
     };
   in
   {
@@ -106,7 +119,6 @@
           ./devices/becky-dingleberry.nix
         ];
       };
-    };
 
       darwinConfigurations = {
         # init with
@@ -130,4 +142,5 @@
         };
       };
     };
+  };
 }